Impingement cooling mechanism, turbine blade, and combustor

ABSTRACT

It has a flat impingement hole ( 2 ) of which the opening width (D 1 ) in the flow direction of a crossflow (F) in the gap between a cooling target ( 10 ) and an opposing member ( 20 ) is set greater than the opening width (D 2 ) in a direction orthogonal with the flow direction of the crossflow F. Accordingly, the cooling efficiency is further improved by the impingement cooling mechanism.

This application is a Continuation of International Application No. PCT/JP2012/078867, filed on Nov. 7, 2012, claiming priority based on Japanese Patent Application No. 2011-244727, filed Nov. 8, 2011, the content of which is incorporated herein by reference in their entity.

TECHNICAL FIELD

The present invention relates to an impingement cooling mechanism, a turbine blade, and a combustor.

BACKGROUND ART

A turbine blade and a combustor, being exposed to high-temperature environments, are sometimes provided with an impingement cooling mechanism for improving the cooling efficiency by raising the heat transfer coefficient.

For example, Patent Document 1 discloses an impingement cooling mechanism having a plurality of circular impingement holes that are formed in an opposing member that is arranged opposing a cooling target.

PRIOR ART DOCUMENTS Patent Documents

-   [Patent Document 1] U.S. Pat. No. 5,100,293

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The flow rate of a crossflow that flows through the gap between the cooling target and the opposing member in which the impingement holes are formed increases as it heads downstream due to the addition of cooling gas that is supplied from the impingement holes to the gap.

For this reason, at the downstream side of the crossflow that flows through the gap between the cooling target and the opposing member, the cooling gas that is blown out from the impingement holes ends up being swept into the crossflow before reaching the cooling target, and so raising the heat-transfer coefficient is difficult.

The present invention was achieved in view of the aforementioned circumstances, and has as its object to further raise the cooling efficiency by an impingement cooling mechanism.

Means for Solving the Problems

The present invention adopts the following constitution as a means for solving the aforementioned issues.

The impingement cooling mechanism according to the first aspect of the present invention, being provided with a cooling target and a plurality of impingement holes formed in an opposing member that is arranged opposing the cooling target, blows out cooling gas from the plurality of impingement holes toward the cooling target, having as the impingement hole at least one flat impingement hole of which the opening width in the flow direction of a crossflow in the gap between the cooling target and the opposing member is greater than the opening width in a direction orthogonal with the flow direction of the crossflow in the gap.

According to the impingement cooling mechanism of the second aspect of the present invention, in the first aspect, the direction in which the opening width of the flat impingement hole becomes the maximum is parallel with the flow direction of a crossflow in the gap between the cooling target and the opposing member.

According to the impingement cooling mechanism of the third aspect of the present invention, the first or second aspect is provided with a turbulent flow forming member that is arranged exposed to a crossflow in the gap between the cooling target and the opposing member.

According to the impingement cooling mechanism of the fourth aspect of the present invention, in the third aspect, the turbulent flow forming member is a protrusion or concavity that is arranged opposing the flat impingement hole and fixed to the cooling target.

The impingement cooling mechanism of the fifth aspect of the present invention is a turbine blade having the impingement cooling mechanism that is any one of the first to fourth aspects.

The impingement cooling mechanism of the sixth aspect of the present invention is a combustor having the impingement cooling mechanism that is any one of the first to fourth aspects.

Effects of the Invention

The present invention has as an impingement hole a flat impingement hole of which the opening width in the flow direction of a crossflow in the gap between the cooling target and the opposing member is set greater than the opening width in a direction orthogonal with the flow direction of the crossflow in the gap.

In this kind of flat impingement hole, since the opening width in the flow direction of the crossflow in the gap between the cooling target and the opposing member is large, it is possible to make the opening width when viewed from the flow direction of the crossflow smaller than a circular impingement hole that blows out cooling gas of the same flow rate. As a result, it is possible to make the collision region between the crossflow in the gap between the cooling target and the opposing member and the cooling gas flow that is blown out from the flat impingement hole narrower than the case of a circular impingement hole, and so it is possible to reduce the influence of the crossflow on the cooling gas flow.

Accordingly, according to the present invention, by blowing out cooling gas from a flat impingement hole, it is possible to cause more of the cooling gas to reach the cooling target than the case of blowing out the cooling gas from a circular impingement hole.

Therefore, according to the present invention, increasing the heat-transfer efficiency and improving the cooling efficiency become possible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view that shows an outline configuration of the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 1B is a schematic view that shows an outline configuration of the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 1C is a schematic view that shows an outline configuration of the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 2A is a plan view that shows a modification of the flat impingement hole provided in the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 2B is a plan view that shows a modification of the flat impingement hole provided in the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 2C is a plan view that shows a modification of the flat impingement hole provided in the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 2D is a plan view that shows a modification of the flat impingement hole provided in the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 2E is a plan view that shows a modification of the flat impingement hole provided in the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 3A is a schematic view that shows an outline configuration of the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 3B is a schematic view that shows an outline configuration of the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 4A is a schematic view that shows a modification of the turbulent flow forming member provided in the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 4B is a schematic view that shows a modification of the turbulent flow forming member provided in the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 5A is a schematic view that shows a modification of the turbulent flow forming member provided in the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 5B is a schematic view that shows a modification of the turbulent flow forming member provided in the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 6A is a schematic view that shows a modification of the turbulent flow forming member provided in the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 6B is a schematic view that shows a modification of the turbulent flow forming member provided in the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 7A is a conceptual view of the analytical model used in the simulation for verifying the effect of the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 7B is a conceptual view of the analytical model used in the simulation for verifying the effect of the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 8 is an explanatory drawing for explaining the patterns of the analytical model used in the simulation for verifying the effect of the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 9 is a graph that shows the simulation result for verifying the effect of the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 10A is a conceptual view of the analytical model used in the simulation for verifying the effect of the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 10B is a conceptual view of the analytical model used in the simulation for verifying the effect of the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 11 is an explanatory drawing for explaining the patterns of the analytical model used in the simulation for verifying the effect of the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 12 is a graph that shows the simulation result for verifying the effect of the impingement cooling mechanism in the second embodiment of the present invention.

FIG. 13A is a schematic view that shows a turbine blade provided with the impingement cooling mechanism in the first embodiment of the present invention.

FIG. 13B is a schematic view that shows a combustor provided with the impingement cooling mechanism in the first embodiment of the present invention.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

Hereinbelow, embodiments of an impingement cooling mechanism, a turbine blade, and a combustor according to the present invention shall be described, referring to the drawings. Note that in the drawings given below, the scale of each member is suitably altered in order to make each member a recognizable size.

First Embodiment of the Impingement Cooling Mechanism

FIG. 1A to FIG. 1C are schematic drawings showing outline configurations of an impingement cooling mechanism 1 of the present embodiment. FIG. 1A is a side cross-sectional view of the impingement cooling mechanism 1, FIG. 1B is a plan view of the opposing wall, and FIG. 1C is an enlarged view of a flat impingement hole.

As shown in these drawings, the impingement cooling mechanism 1 has a plurality of the flat impingement holes 2 that are formed in an opposing wall 20 (opposing member) that is arranged opposing a cooling target 10.

The impingement cooling mechanism 1 cools the cooling target 10 by blowing out cooling gas from the flat impingement holes 2 toward the cooling target 10.

As shown in FIG. 1B, a plurality of the flat impingement holes 2 are provided evenly spaced in the opposing wall 20.

As shown in FIG. 1C, the opening shape of each flat impingement hole 2 is set to a race track shape that is formed by two parallel sides and circular arcs that connect those sides.

Also, as shown in FIG. 1C, the flat impingement hole 2 is arranged so that the long axis thereof is parallel with the flow direction of a crossflow F in the gap between the cooling target 10 and the opposing wall 20. Thereby, the direction of the maximum opening width is made to be parallel with the crossflow F.

In the flat impingement hole 2 that is arranged as described above, since the long axis is oriented in the flow direction of the crossflow F, and the short axis is oriented in the direction orthogonal with the flow direction of the crossflow F, the opening width D1 in the flow direction of the crossflow F is set to be greater than the opening width D2 in the direction that is orthogonal with the flow direction of the crossflow F.

The size of this kind of flat impingement hole 2 is set so that the opening area is the same as the circular impingement hole 100 that has been conventionally used. As a result, as shown in FIG. 1C, the opening width D2 of the flat impingement hole 2 is narrower than the diameter Da of the conventional circular impingement hole 100.

Note that the ratio of the opening width D1 and the opening width D2 of the flat impingement hole 2 is set by manufacturing limits and the like.

For example, if the opening width D1 becomes too wide, it will interfere with the flat impingement hole 2 that is adjacent in the flow direction of the crossflow F, and so the shape of the flat impingement hole 2 will no longer be maintainable. Accordingly, it is necessary to set the opening width D1 within a range that does not interfere with the flat impingement hole 2 that is adjacent in the flow direction of the crossflow F. Once the opening width D1 is determined, the opening width D2 for making the same opening area as the conventionally used circular impingement hole 100 is unambiguously determined, whereby the ratio of the opening width D1 and the opening width D2 is determined.

Note that in the case of the flat impingement hole 2 being arranged at a narrow pitch in the flow direction of the crossflow F so that the opening width D1 cannot be secured sufficiently wide, it is possible to secure the width of the opening width D1 by arranging the flat impingement holes 2 in a staggered shape.

The impingement cooling mechanism 1 of the present embodiment having this kind of constitution has as an impingement hole the flat impingement hole 2 in which the opening width D1 in the flow direction of the crossflow F in the gap between the cooling target 10 and the opposing wall 20 is greater than the opening width D2 in the direction orthogonal with the flow direction of the crossflow F.

In this kind of flat impingement hole 2, since the opening width D1 in the flow direction of the crossflow F is large, it is possible to make the opening width when viewed from the flow direction of the crossflow F smaller than a circular impingement hole that blows out cooling gas of the same flow rate. As a result, it is possible to make the collision region between the crossflow F and the cooling gas flow G that is blown out from the flat impingement hole 2 narrower than the case of a circular impingement hole, and so it is possible to reduce the influence of the crossflow F on the cooling gas flow G.

Accordingly, with the impingement cooling mechanism 1 of the present embodiment, by blowing out the cooling gas from the flat impingement hole 2, the cooling gas is less prone to the influence of being bent by the crossflow F than the case of blowing out the cooling gas from the circular impingement hole. Therefore, the heat-transfer efficiency is increased, and so it becomes possible to improve the cooling efficiency.

Note that in the impingement cooling mechanism 1 of the present embodiment, the constitution is adopted of all of the impingement holes being flat impingement holes 2.

However, it is not always necessary for all of the impingement holes to be flat impingement holes 2.

For example, the influence of the crossflow F on the cooling gas is greater at the downstream where the flow rate of the crossflow F increases. For that reason, it is acceptable for only those at the downstream of the crossflow F to be flat impingement holes 2. In this situation, it is possible to reduce the number of flat impingement holes 2, whose processing cost is greater than circular impingement holes, and so it is possible to reduce the manufacturing cost of the impingement cooling mechanism 1.

Also, in the impingement cooling mechanism 1 of the present embodiment, the constitution is described of the opening shape of the flat impingement hole 2 being a racetrack shape.

However, provided the opening width in the flow direction of the crossflow F is set to be greater than the opening width in the direction that is orthogonal with the flow direction of the crossflow F, the opening shape of the flat impingement hole in the present invention does not necessarily need to be a racetrack shape.

For example, it is possible to adopt a flat impingement hole 2A with an oval opening shape as shown in FIG. 2A. Also, it is possible to adopt a flat impingement hole 2B with a square opening shape as shown in FIG. 2B. Also, it is possible to adopt a flat impingement hole 2C that is an isosceles triangle of which the distal end faces the downstream of the crossflow F as shown in FIG. 2C. Also, it is possible to adopt a flat impingement hole 2D that is an isosceles triangle of which the distal end faces the upstream of the crossflow F as shown in FIG. 2D. Also, it is possible to adopt a diamond-shaped flat impingement hole 2E as shown in FIG. 2E.

Second Embodiment of the Impingement Cooling Mechanism

Next, a second embodiment of the impingement cooling mechanism of the present invention shall be described. Note that in the description of the present embodiment, descriptions of those portions that are the same as in the first embodiment of the impingement cooling mechanism described above shall be omitted or simplified.

FIG. 3A and FIG. 3B are schematic drawings showing outline configurations of an impingement cooling mechanism 1A of the present embodiment, with FIG. 3A being a side cross-sectional view of the impingement cooling mechanism 1A, and FIG. 3B being a plan view of the cooling target.

As shown in these drawings, the impingement cooling mechanism 1A is provided with a plurality of protrusions 3 (turbulent flow forming member) that are arranged exposed to the crossflow F.

This protrusion 3 is arranged opposite to the flat impingement hole 2 and fixed to the cooling target 10, to form a turbulent flow in the gap between the cooling target 10 and the opposing wall 20.

According to the impingement cooling mechanism 1 of the present embodiment that has this kind of constitution, a turbulent flow is formed in the gap between the cooling target 10 and the opposing wall 20 by the protrusion 3, the heat-transfer efficiency is increased, and so it is possible to improve the cooling efficiency.

Note that in the impingement cooling mechanism 1 of the present embodiment, the constitution is adopted in which the turbulent flow forming member of the present invention is the protrusion 3 that is provided with respect to each flat impingement hole 2.

However, the turbulent flow forming member of the present invention need only be capable of forming a turbulent flow in the gap between the cooling target 10 and the opposing wall 20.

For example, as shown in FIG. 4A and FIG. 4B, it is also possible to use a dimple 3A that is provided with respect to each flat impingement hole 2 as the turbulent flow forming member of the present invention. Also, as shown in FIG. 5A and FIG. 5B, it is also possible to use a slot (concavity) 3B that extends in a direction orthogonal with the flow direction of the crossflow F as the turbulent flow forming member of the present invention. Also, as shown in FIG. 6A and FIG. 6B, it is also possible to use a protrusion 3C that extends in a direction orthogonal with the flow direction of the crossflow F as the turbulent flow forming member of the present invention.

(Simulation Result of the Impingement Cooling Mechanism)

A simulation is performed to verify the effect of the impingement cooling mechanism 1 of the first embodiment mentioned above.

As shown in FIG. 7A and FIG. 7B, this simulation uses an analytical model that provides a discharge hole on the downstream of the impingement holes in the array direction, and moreover has a flow passage for the main flow gas on the outer side region of the discharge hole.

Moreover, in this simulation, as shown in FIG. 8, the analysis is performed for one having the impingement hole be a conventional impingement hole whose opening shape is circular (A-1), one having the impingement hole be a flat impingement hole in which the opening shape is a racetrack shape with the long axis thereof parallel to the crossflow (corresponding to the flat impingement hole 2 of the aforementioned first embodiment) (A-2), one having the impingement hole be a flat impingement hole in which the opening shape is a racetrack shape with the long axis thereof orthogonal with the crossflow (A-3), and one having the impingement hole be a flat impingement hole in which the opening shape is a racetrack shape with the long axis thereof intersecting the crossflow at 45° (A-4).

FIG. 9 shows the result, in which A-2 is confirmed as being the most superior in terms of the average heat transfer coefficient. That is to say, it is confirmed that by using the flat impingement hole of the aforementioned first embodiment, it is possible to raise the heat transfer coefficient by more than a conventional circular impingement hole.

Moreover, from the fact that A-2 is the most superior, it is found that the maximum opening width direction being made to be parallel with the flow direction of the crossflow contributed greatly to the improvement of the average heat transfer coefficient. Accordingly, from the standpoint of the average heat transfer coefficient, arranging the flat impingement hole so that its long axis is parallel with the flow direction of the crossflow is preferred.

Next, a simulation is performed to verify the effect of the impingement cooling mechanism 1A of the second embodiment described above.

As shown in FIG. 10A and FIG. 10B, in the present simulation, an analysis is performed using an analytical model in which protrusions are added to the analytical model shown in FIG. 7A and FIG. 7B.

Also, in this simulation, the analysis is performed for one having the impingement holes all be flat impingement holes of which the opening shape is a racetrack shape, with the long axis thereof made parallel with the crossflow, and in which, as shown in FIG. 11, the impingement holes viewed from the cooling gas injection direction are arranged between the protrusions (B-1), one in which the impingement holes are further removed from the protrusion array direction from the arrangement position of B-1 (B-2), and one in which the impingement holes, viewed from the cooling gas injection direction, are arranged overlapping with the protrusions (B-3).

FIG. 12 shows the result, in which B-3 is confirmed as being the most superior in terms of the average heat transfer coefficient. That is to say, the one in which the flat impingement holes, viewed from the cooling gas injection direction, are arranged overlapping with the protrusions, in other words, the constitution in which the protrusions are arranged opposing the flat impingement holes, is preferred from the standpoint of the average heat transfer coefficient.

(Turbine Blade and Combustor)

FIG. 13A and FIG. 13B are schematic drawings that show a turbine blade 30 and a combustor 40 provided with the impingement cooling mechanism 1 of the first embodiment described above. FIG. 13A is a cross-sectional view of a turbine blade, and FIG. 13B is a cross-sectional view of a combustor.

As shown in FIG. 13A, the turbine blade 30 has a double-shell structure that is provided with an outer wall 31 and an inner wall 32. The outer wall 31 corresponds to the aforementioned cooling target 10, while the inner wall 32 corresponds to the aforementioned opposing wall 20. The turbine blade 30 is provided with the impingement cooling mechanism 1 having flat impingement holes provided in the inner wall 32.

According to the impingement cooling mechanism 1 of the first embodiment, since it is possible to improve the cooling efficiency by increasing the heat transfer coefficient, the turbine blade 30 provided with this kind of impingement cooling mechanism 1 has excellent heat resistance.

As shown in FIG. 13B, the combustor 40 has a double-shell structure that is provided with an inner liner 41 and an outer liner 42. The inner liner 41 corresponds to the cooling target 10 mentioned above. The combustor 40 is provided with the impingement cooling mechanism 1 having flat impingement holes provided in the outer liner 42, which corresponds to the aforementioned opposing wall 20.

Since the impingement cooling mechanism 1 of the aforementioned first embodiment is capable of improving the cooling efficiency by increasing the heat transfer coefficient, the combustor 40 that is provided with this kind of impingement cooling mechanism 1 has excellent heat resistance.

Note that it is also possible to adopt constitutions of the turbine blade 30 and the combustor 40 being provided with the impingement cooling mechanism 1A of the aforementioned second embodiment instead of the impingement cooling mechanism 1 of the aforementioned first embodiment.

Hereinabove, preferred embodiments of the present invention have been described with reference to the appended drawings, but it goes without saying that the present invention is not limited to the aforementioned embodiments. The various shapes and combinations of each constituent member shown in the embodiments refer to only a single example, and may be altered in various ways based on design requirements and so forth within a scope that does not deviate from the subject matter of the present invention.

INDUSTRIAL APPLICABILITY

In an impingement cooling mechanism that blows out cooling gas from a plurality of impingement holes formed in an opposing member arranged opposing a cooling target toward the cooling target, by blowing out the cooling gas from a flat impingement hole, it is possible to cause more of the cooling gas to reach the cooling target than the case of blowing out the cooling gas from a circular impingement hole. Thereby, it is possible to increase the heat-transfer efficiency and improve the cooling efficiency.

DESCRIPTION OF THE REFERENCE SYMBOLS

1, 1A: Impingement cooling mechanism

2, 2A, 2B, 2C, 2D, 2E: Flat impingement hole

3: Protrusion (turbulent flow forming member)

3A: Dimple (turbulent flow forming member)

3B: Slot (turbulent flow forming member)

3C: Protrusion (turbulent flow forming member)

10: Cooling target

20: Opposing wall (opposing member)

D1: Opening width in crossflow direction

D2: Opening width in direction orthogonal with crossflow direction

F: Crossflow

30: Turbine blade

31: Outer wall

32: Inner wall

40: Combustor

41: Inner liner

42: Outer liner 

1. An impingement cooling mechanism comprising: a cooling target; an opposing member that is arranged opposing the cooling target; and a plurality of impingement holes formed in the opposing member, that blows out cooling gas from the plurality of impingement holes toward the cooling target; wherein the impingement cooling mechanism has as the impingement hole at least one flat impingement hole of which the opening width in the flow direction of a crossflow in the gap between the cooling target and the opposing member is greater than the opening width in a direction orthogonal with the flow direction of the crossflow in the gap.
 2. The impingement cooling mechanism according to claim 1, wherein the direction in which the opening width of the flat impingement hole becomes the maximum is parallel with the flow direction of a crossflow in the gap between the cooling target and the opposing member.
 3. The impingement cooling mechanism according to claim 1, further comprising a turbulent flow forming member that is arranged exposed to a crossflow in the gap between the cooling target and the opposing member.
 4. The impingement cooling mechanism according to claim 2, further comprising a turbulent flow forming member that is arranged exposed to a crossflow in the gap between the cooling target and the opposing member.
 5. The impingement cooling mechanism according to claim 3, wherein the turbulent flow forming member is a protrusion or concavity that is arranged opposing the flat impingement hole and fixed to the cooling target.
 6. The impingement cooling mechanism according to claim 4, wherein the turbulent flow forming member is a protrusion or concavity that is arranged opposing the flat impingement hole and fixed to the cooling target.
 7. A turbine blade comprising the impingement cooling mechanism according to claim
 1. 8. A turbine blade comprising the impingement cooling mechanism according to claim
 2. 9. A turbine blade comprising the impingement cooling mechanism according to claim
 3. 10. A turbine blade comprising the impingement cooling mechanism according to claim
 4. 11. A turbine blade comprising the impingement cooling mechanism according to claim
 5. 12. A turbine blade comprising the impingement cooling mechanism according to claim
 6. 13. A combustor comprising the impingement cooling mechanism according to claim
 1. 14. A combustor comprising the impingement cooling mechanism according to claim
 2. 15. A combustor comprising the impingement cooling mechanism according to claim
 3. 16. A combustor comprising the impingement cooling mechanism according to claim
 4. 17. A combustor comprising the impingement cooling mechanism according to claim
 5. 18. A combustor comprising the impingement cooling mechanism according to claim
 6. 